In order to purify a virus it is necessary to remove host cell proteins and DNA from the virus sample. Unfortunately, current methods of removing host cell proteins and DNA are accompanied by loss of a significant amount of virus. Typically, for a flavivirus, recovery of the virus from filtration processes are generally about ten to twenty percent and typically less than 10 percent. Following purification, another problem is aggregation or clumping together of the purified virus particles.
Prior art methods of purification and concentration of a virus, e.g., often use ultracentrifugation wherein sucrose is required in order to run the gradient for the separation. Such ultracentrifugation generally results in the undesirable presence of sucrose in the final virus sample. In order to obtain a virus sample that is free of sucrose, tangential flow filtration (TFF) is frequently used to separate the virus from proteins and other compounds. However, use of TFF for such a purification tends to result in significant loss of virus.
Prior art methods of purification and concentration of a virus, e.g., often use ultracentrifugation wherein sucrose is required in order to run the gradient for the separation. Such ultracentrifugation generally results in the undesirable presence of sucrose in the final virus sample. In order to obtain a virus sample that is free of sucrose, tangential flow filtration (TFF) is frequently used to separate the virus from proteins and other compounds. However, use of TFF for such a purification tends to result in significant loss of virus. As well, currently used methods of virus purification thus have been accompanied by ongoing problems including low yield or loss of virus, host cell protein levels higher than desirable, high sucrose levels, and aggregation of the purified virus particles. Such methods have also been difficult to use in single use or disposable technologies.